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TINA/Spice: LM2904M/NOPB: Spice model with min max output currents

David Lynch26
Prodigy 30 points
Other Parts Discussed in Thread: TINA-TI, LM2904

Tool/software: TINA-TI or Spice Models

Is there a model or multiple models  for this opamp that has (have) the output current adjustable or at least set to the minimum and maximum sink/source values.

I have a circuit that needs to have components selected to allow operation over entire output current range for part.

  • 0
    TI__Genius 9775 points

    Hi David,

    I use the TINA-TI version of the model by downloading TINA-TI software, and then go to Spice Macros section -> Operational Amplifiers -> LM2904. I have found that the model does have current limit of about +/-35mA

    Attached is my test bench.

    sim_isc_LM2904.TSC

  • 0 in reply to Herman Theodorus
    Prodigy 30 points
    I am looking for a model that will allow me to simulate at the devices minimum and typical output current levels:
    Minimum source current of 20mA and a minimum sink current of 10 mA.
    The models have polynomials for their poutput currents which I am unable to decipher.
    I have a circuit that was designed many years ago that is sensitive to output voltage level and therefore current drive into that output load, over first stage opamp (running as oscillator) going into an inductive/resistive load which is level sensed to determine trigger point of second opamp (running as a comparator).
    I need a model that will allow me to set to outcurrents, sink and source for the opamp (2N2904N dual SOIC 8 ppins package).
    Please let me know.
  • 0 in reply to David Lynch26
    TI__Genius 9775 points
    David,

    After giving it a try, please try to change R16 and R17 inside the model to reduce or to increase your source and sink current. On my experiment for your Source 20mA and Sink of 10mA, R16 and R17 would be around 70 and 30 ohms respectively instead of 17.5 ohms for both as shown in the original model.

    Herman
  • 0 in reply to Herman Theodorus
    Prodigy 30 points
    Where do I get the LM2904 model and how do I open (see) it in schematic format?
  • 0 in reply to David Lynch26
    TI__Genius 9775 points
    Hi David,

    We don't have the schematic format for this one. To figure it out, I am pretty much have to go through the output stage section of the text netlist, then from there using experience, instinct and a bit of trial and error to figure out which components controls the Isc min and Isc max.

    To get the text netlist:
    1. Please download our TINA-TI here www.ti.com/.../tina-ti

    2. Then once you have the simulator program open, go to upper tab that says " Spice Macros" -> Then go to button/section that says "Operational Amplifiers" -> LM2904.

    3. Put the model into the schematic screen. Double click the symbol. Then click button that says "Enter Macro". From there you can "save as" or "copy paste" the text netlist to create separate model file. If you want use TINA-TI as your simulator, you can just modify it within that TINA text editor -> Close button -> Save.

    Hope this helps
    Herman